Weather Service: Heat Feels Like 100 to 110 Degrees

The oppressive heat wave that has roasted parts of the Midwest is spreading to the eastern part of the country, according to the National Weather Service.

More than 30 states have heat warnings and advisories, the Weather Service said, and temperatures in parts of the country will fell like 100 to 110 degrees or higher by this afternoon.

By Thursday, "across the mid-Atlantic and parts of the Southeast" temperatures are expected to rise and continue throughout the weekend, the Weather Service said. About 40 states across the country reached highs of at least 90 degress in some areas on Tuesday.

The heat wave is so dangerous because temperatures feel hot all day — even at night. Chicago tied its record for the warmest low temperature of 78 degreeson Tuesday . In Rockford, Ill., temperatures dropped to only 76 degrees — the warmest on record.

The heat wave in recent days has brought heat index values, which measure how hot it feels, to as high as 131.

Minneapolis, Minnesota, recorded its highest dew point ever, 82 degrees, on Tuesday. The dew point temperature is a measure of atmospheric moisture.

The stubborn heat wave blasting the U.S. midsection was blamed for more deaths on Tuesday.

Two men appeared to have died while tending to yards. The core body temperature of a 65-year-old man who died on Monday while mowing his lawn near Wichita, Kan., was 107 degrees, Butler County Sheriff Kelly Herzet said.

"It's tragic," Herzet said. "People need to stay in when it's this hot, or drink plenty of liquids. They need to know their limits."

It was a similar story about 65 miles away in Blackwell, Okla., where a 70-year-old man last seen walking down a street pushing a lawnmower was found unresponsive. He died at the hospital. His body temperature was at least 108 degrees, according to police.

"This is a guy you would see out all the time in all different weather," said Blackwell Fire Chief Tom Beliel. "It's just unfortunate."

Heat, the leading weather-related killer in the United States, has resulted in at least 13 deaths across the Midwest since last week, the National Weather Service reported.

Across the Midwest, there were jaw-dropping heat indexes — measured as a combination of temperature and humidity. It felt like 131 degrees in Knoxville, in central Iowa, and 124 in Freeport, Ill., the Weather Service said.

"This is completely out of whack for the Upper Midwest," said Chris Vaccaro, a Weather Service spokesman. "We've got several more days on tap" of excessive heat.

The heat also set new peak records for electricity usage.

Xcel Energy, which serves 1.64 million customers in North Dakota, South Dakota, Wisconsin, and Minnesota, broke a demand record on Monday with 9,504 megawatts of power used, said Tom Hoen, a company spokesman. The previous record set in August 2010 was 9,100 megawatts.

Utility companies in Iowa also reported record usage and said they could top those records again on Tuesday.

Parts of 32 states plus Washington, D.C., were under heat advisories, warnings or watches as the heat wave expanded eastward. Actual temperatures in Washington and New York are expected to flirt with 100 degrees in the coming days.

In Omaha, Nebraska, flood control work along the overflowing Missouri River was halted due to the heat, as officials worried that filling sandbags was too strenuous.

In Illinois, the second-largest corn- and soybean-producing state, the heat and humidity were not yet damaging crops, according to University of Illinois agronomist Emerson Nafziger. But a lack of rain is propelling concern.

"Corn is holding on so far," Nafziger said. "We're starting to get a little worrie